(a) What mass of potassium nitrate would be needed to
produce a saturated solution of potassium nitrate in
50 grams of water at 313 K?
(b) Pragya makes a saturated solution of potassium chloride
in water at 353 K and leaves the solution to cool at room
temperature. What would she observe as the solution
cools? Explain.
(c) Find the solubility of each salt at 293 K. Which salt has
the highest solubility at this temperature?
d)What is the effect of change of temperature on the
solubility of a salt?
Answers
Answer:
Explanation:
(a) The mass of water given is 50 grams, so since it is just the half of hundred grams the amount of potassium nitrate required will also be just the half of 62 grams, that is 31 grams. So, 31 grams of potassium nitrate will form a saturated solution with 50 grams of water at 313 Kelvin.
(b) The amount of potassium chloride that should be dissolved in water to make saturated solution increases with temperature. Thus when the solution cools some of potassium chloride will precipitate out of the solution.
(c) The solubility of Sodium chloride at 293 K is = 36 g. The solubility of Potassium chloride at 293 K is = 35 g. The solubility of Ammonium chloride at 293 K is = 37 g. Therefore the solubility of Ammonium chloride is highest at this temperature.
(d) Increasing the temperature increases the solubilities of substances. For example, sugar and salt are more soluble in water at higher temperatures. But, as the temperature increases, the solubility of a gas in a liquid decreases. As temperature increases, the average kinetic energy of the gas molecules increases.